Pivot means for firearm elements



2 Sheets-Sheet l "r. R. ROBINSON, JR

Filed Aug. 27, 194s PIVOT-MEANS FOR FIREARM ELEMENTS W :Ni .www a R am. nu. n E Nm .hwwwl May so, 1944.

May 30, 1944.

T. R. RoBlNsoN, JR 2,350,131

PIVOT-MEANS FOR FIREARM ELEMENTS Filed Aug. 27, 1943 2 Sheets-Sheet 2 227. E? @go/#49 Z? 30,133/36 Z :n ld8 l 135 37 i #Z j'rll Z'L [Z8 33 50 M9 g5 ZW 7 30 /dg Z9 g a u# "#5 -T- -H'- #e #e Patented May 30, 1944 2,350,131 'Pryor MEANS Fon FIREARM ELEMENTS Thomas R. Robinson, Jr., New Haven, Conn., assignor to The High Standard Manufacturing Company, Hamden, Conn., a corporation of Connecticut 3 Claims.

The present invention relates to improvements in pivot-means for rearm elements, i. e., pivotmeans whereby ejectors, triggers, sears and other swinging members of a firearm may be pivotally connected to another member or feature of the rearm-structure. v

One of the main objects of the present invention is to provide superior pivot-means fo-r lirearms in which is included a pivot-'pin or its equivalent and in which the parts are so constructed and arranged that the stresses imposed upon such a pivot-pin in guarding it against axial displacement, are in the nature of axially-applied compressive stresses, rather than tensional stresses.

Another object of the preseritinvention` is to provide superior pivot-means for rearm-structures in which is included a pivot-pin or its equivalent and in which provision is made whereby, in the event of the pivot-pin being broken into two parts by .a transverse fracture, the parts of the said pivot-pin will be effectively prevented from harmful axial separation.

A further object of the present invention is to provide superior pivot-means for firearm elements which will combine both of the general advantages above referred to in a structure which may be produced at a low cost for manufacture.

With the above and other objects in view, as will appear to those skilled in the. art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. l is a View in side elevation of a machine gun equipped with the present invention;

Fig. 2a is a broken view partly in side elevation and partly in vertical central-longitudinal section of the rear portion of the machine gun shown in Fig. l with the parts shown in the positions which they assume when the breech-bolt iS in its'normal breech-closing position;

Fig. 2b is a similar view of the forward portion or' the machine gun;

Fig. 3 is a view in side elevation of the extractor-and-ejector unit, detached;

Fig. 4 is a view thereof in front-end elevation;

Fig. 5 is a top or planview thereof;

Fig. 6 is a transverse sectional view taken on the line 6-6 of Fig. 3 but onv a larger scale;

Fig. 7 is a view corresponding to Fig. 6 but showing the pivot-pin prior to the same having its end expanded to form, thelip-like stop-abutment; f

reputation ugust 27, 1943, serial No. 500,192

Fig. 8 is a broken sectional perspective view of the outer end-portion of the extractor stripped of the pivot-pin, ejector and ejector-spring;

Fig. 9 is a perspective view partly in section of the pivot-pin prior to having its stop-abutment expanded; and

Fig. 10 is a perspective view of the ejector.

The particular machine gun herein chosen foi` purposes of illustrating one form of the present invention, is of the so-called Browning type and is of the general character illustrated in more detail in United States Patent No. 1,628,226, dated May l0, 1927.

Inasmuch as the present invention relates t pivot-means for the firearm elements, only a brief description will be made of the major features of the particular machine gun in which the present invention is incorporated for purposes of illustration.

The machine gun illustrated in the accompanying drawings includes a receiver generally designated by the reference character 2U, an axiallyreciprocating barrel 2|, a barrel-extension 22, a breech-bolt 23 and a barrel-jacket 24.

The barrel 2l has its rear portion extended within the receiver 20 for reciprocation therein and the aforesaid barrel-extension is organized with the yrear-end of the barrel for reciprocation also within the receiver 20, in a manner well known in the art.

The breech-bolt 23reciprocates both with and with respect to the barrel-extension 22 in a manner well known in the art, and is yieldingly urged forwardly into its breech-closing position by a helical breech-closing spring 25. Pivotally mounted to one side of the breech-bolt 23 is an extractor-and-ejector unit generally designated by the reference character 26. The pivotal mounting of the unit 26 is effected by means of a stud 27 rigidly offsetting laterally from the inner face of the rear portion of the bar-like arm 28 of a cartridge-extracting member 29. At its forward end the cartridge-extracting member 29 includes a head 30, preferably forged or otherwise made integral with the bar-like arm 28. At its rear lower corner adjacent its outer end the head 3l! of the cartridge-extracting member 29 is formed with a cartridge-extracting hook 3l adapted in a manner Well known in the art to successively fit into the respective cannelures of a series of cartridges to effect the successive individual extraetions thereof from a cartridge-belt 32 indicated in Figs. 1 and 2a.

Immediately adjacent the inner face of the arm 2B, the head 30 of the member 29 is formed with a longitudinally-extending notch or gap 33 formed on the underside of the said head and opening downwardly as well as to the iront and rear thereof. The notch 33 as thus formed creates a gap between what might be aptly described as two wall-portions respectively designated 34 and 35. The wall-portion 34 is formed with a pin-receiving, passage 36 which is axially in line with a complemental"pin-receiving passage 31 formed in the wall-portion 35. Both of the passages 36 and 31 just referred to stand substan-vv tially perpendicularly with respectto vthe plane of the bar-like arm 2B of the vcartridge-extracting member 29 and hence extend substantially perpendicularly with respect tothe longitudinal-axis of the machine-gun structure... l

Immediately adjacent the outer end of the pin- K receiving passage 36 in nthe .wall-portion '34, the

said wall-portion is formed with an upwardlyopening substantially-semicircular groove 38, `the Vouter wall of which constitutesa stop-abutment 3,9 y'which vfaces inwardly toward the notch or gap 33. The complemental prin-receiving passage`31 inthe wall-portion V35 has.' two 'diameters as shown and at the junction of itsV `two said diarrieters it provides an annular stop-a`.b1'1trne`ntY 40 facinginwardly toward 4the notch or gap 33 and hence toward and in opposition-to the comple- `'mental stop-abutmentv 39 adjacent the pin-receiv'ing passage'- 36. z Y Extending across the notch 0i gap 33 inthe head 30` of the cartridge-extractingfmember 29 and fitting at its respective opposite ends `i'nto ,the pin-receiving passages A36 and 31,'is-.a pivotpinrgenerally designated lby the reference character 4I. 'Ihe said pivot-'pin 4I includes a ,cylin- .drical' body-portion 42v of relatively-large diend, and a aring head 44 formedatfthe end of the. pivot-pinopposite its said stern 43. The sterrrA 43 of thepivot-pin 4I `is of a lesser diameter than the integral-bodyportionw42 thereof and the saidv relationship results in the formation on vproduced byv providing the adjacent end of the pivot-pin4l 1with a cavity 46 from which the lmetal may be ared outwardly to form the'said head`l44. f: Extendinglupwardly into the notch orgap 33 in the head 30 ofthe cartridge-extracting member 29 is the apertured upper end of a cartridgeejecting-member 41; The :body-portion 42 of the pivot-pin`4l extends'through thek apertured -upper end of the `said member 41 and 'serves' to lorganize the "said: member withI 'the cartridgeextracting member 29 to constitute. together lwith Iother associated'parts, the' extractor-and'- ejectorv unit' 26v before referred to' and especially well shown in Figs. 3, 4, and 5. At its lower end the cartridge-ejecting' memberf41 is curved inwardly toward the breech-bolt'23 A'to' provide va -finger 48, the upper surface of which serves 'under some conditonsto retain a cartridge against downward movement and in other AinstancesI the v luider face of the saidlfingerserves to downwardly eject a cartridge. Y

Aor gap 33. The `said ejector-spring 49 is formed at its lower end with a. depending-tail 5| normally pressing against the upper portion of the -ameter, a cylindrically-contoured stem 43 at one outer face of the cartridge-ejecting member 41. The downward thrust of the ejector-spring 49 is mainly onthe top of the cartridge-ejecting member 41 adjacent the outer face thereof, so

that the tendency of the said spring is to yieldingly maintain the said member in the position in. which it is vshown byfu-ll Llines in- Figs. g4, 6 and 7,7whileV permitting the said ejector to be swung into the position in lwhich itis indicated by brokenlines in Fig. 4..; 2

In assemblingthe extractor-andejector unit 26, the ejector-spring 49 is positioned as shown in Fig. '1, as is alsol the cartridge-ejecting member 41. The pivot-pin. lwith its.` head 44 still unexpanded, is slid Vinto the .two complemental pin-receivingpassages 36 and 31andvthrou'gh the apertured upper end of the cartridge-ejectg ing member. 4,1 until'thejsaid: parts assume sub'- stantially `the positionsrin whichv they aresh'own in Fig. '7. Now by means ofa suitable tool which may be inserted into the cavity 46, the adjacent end of vthe pivot-pin Amay be expandedl to form `the-,head 44v (Fig. 6 `ito thereby force a portionfof the said vhead'into the groove 38-of the head 30 andengage aV portionofthe resultant lip-like 'stop-abutment 44a into-engagement with the inwardly-facingstop-abutment 39. The body-portion 42 of the pivot-pin`4las thus mounted, is prevented'from axialdisplacement by' the engagement of its 'complemental outwardly-facing stop-abutments V44a. and 45 `respectively withr the inwardly-macing stop-abutments 39 and 40 in the head 30 oi?` themernber 29. Thus, Vany effort to axially displace the pivot-pin 4I subjects the Vsame to a compressive strain, rather than to a tension. strain. In the event that the pivot-pin 4Ir should becometransversely cracked or broken, the'two' resulting parts will be still held in place and the said parts will not lbe able to work their way axially outward to jam or otherwise damage the machine-gun mechanism. i l

The invention mayjbe carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, andthe present embodiments are, therefore, to Abe considered in all respects as illustrative and'not-restrictive, and all changes comingV withinA the meaning and equivalency range of the' appended claims are intended to be embraced therein.'

Iclaim: i y

1. Pivot-means forrlrearm elementainclud ing in combination: 'a ,first rearm-memberhaving two complemental laterally-spaced-apart wall-portions l'l'zafvili'gav gap therebetween for the reception of a second rearm-membeneach of l the said wall-portions having Aa lpin-receiving passage .y extending substantiallyv coaxially with respect to the similar passage in the other wallportion, each of the said pin-receiving passages intersecting at its inner end the gap between the said wall-portions, each of the said wall-portions having one of two stop-abutments adjacent an outward portion of its pin-receiving passage and facing inwardly toward the gap between the said wall-portions and in opposition to the stopabutment in the complemental wall-portions; a second firearm-member having a portion extending into the gap between the two complemental wall-portions of the said first rearm-memben and having an aperture therethrough registering with the respective passages in the said coin plemental wall-portions; and a pivot-pin extending in the two said pin-receiving passages and through the said aperture, the said pivot-pin having two integral complemental stop-abutments facing outwardly away from each other and respectively positioned to engage with the respec tive inwardly-facing stop-abutments respectively formed in the two said complemental wall-portions of the said first firearm-member.

2. Pivot-means for firearm elements, including in combination: a first firearm-member having two complemental laterally-spaced-apart Wallportions having a gap therebetween for the reception of a second firearm-member, each of the said wall-portions having a pin-receiving passage extending substantially coaxially with respect to the similar passage in the other wall-portion, each of the said pin-receiving passages intersecting at its inner end the gap between the said wall-portions, each of the said wall-portions having one of two stop-abutments adjacent an outward portion of its pin-receiving passage and facing inwardly toward the gap between the said wall-portions and in opposition to the stop-abutment in the complemental wall-portions; a second firearm-member having a portion extending into the gap between the two complementa] wallportions of the said iirst firearm-member and having an aperture therethrough registering with the respective passages in the said complementa] wall-portions; and a pivot-pin extending in the two said pin-receiving passages and through the said aperture, the said pivot-pin having two integral complemental stop-abutments facing outwardly away from each other and respectively positioned to engage with the respective inwardly-facing stop-abutments respectively formed in the two said complementa). wall-portions of the said first firearm-member, one of the said stopabutments of the pivot-pin being in the form of an outwardly-bent integral stop-lip.

3. Pivot-means for rearm elements, including in combination: a rst firearm-member having two complemental laterally-spaced-apart wallportions having a gap therebetween for the reception of a second firearm-member, each of the said wall-portions having a pin-receiving passage extending substantially coaxially with respect to the similar passage in the other wall-portion, each of the said pin-receiving passages intersecting at its inner end the gap between the said wall-portions, each of the said wall-portions having one of two stop-abutments adjacent an outward portion of its pin-receiving passage and facing inwardly toward the gap between the said wall-portions and in opposition to the stop-abutment in the complemental wall-portions; a second rearm-member having a portion extending into the gap between the two complemental wallportions of the said first firearm-member and having an aperture therethrough registering with the respective passages in the said complemental wall-portions; and a pivot-pin extending in the two said pin-receiving passages and through the said aperture, the said pivot-pin having a stem at one end of a diameter smaller than the bodyportion of the pivot-pin, the said pivot-pin being formed at the junction of its body-portion and the said stem with an outwardly-facing stopabutment positioned to engage with the adjacent one of the two inwardly-facing stop-abutments formed in the said rst firearm-member, the said pivot-pin also having at its end opposite its said stem an outwardly-bent stop-1ip having its outer end engaged with the other of the two stopabutments of the said rst firearm-member.

THOMAS R; ROBINSON, JR. 

